Effect of Plant Starch on the Production of Glucoamylase from Aspergillus niger

Abstract. Glucoamylase is an inducible enzyme and generally induced in the presence of starch. Corn starch, wheat starch, sweet potato starch and potato starch were used as the carbon sources to produce the glucoamylase by A. niger FJL0801. The results showed that the maximum glucoamylase activity was 594.511.7 U/mL when 4% sweet potato starch was used as the carbon source, its enzyme activity was increased by 34.9% than potato starch, by 17.2% than wheat starch and by 4.6% than corn starch. In the four media, the adaptive phage of A. niger FJL0801 were all 0-12 h, the logarithmic growth phase all 12-60 h, and the stationary phase all 60-192 h. The maximum biomass of the strain was 1.950.09 μg/mL in the corn starch medium. The glucoamylase activity was inversely proportional to the growth rate of A. niger FJL0801. The final pH value was all within 6.960.057.110.07 in the four midia. There was no significant difference at 0.05 probability level between the pH of the four media at the same fermentation time. The pH change was not the reason for glucoamylase activity by A. niger FJL0801 used different plant starch.